Geometrical instrument



Aug. 8, 1933. H. DAWSON GEOMETRICAL INSTRUMENT 2 Sheets-Sheet 1 Original Filed March 25, 1927 swam/K00 Qw 5f" Daw/w vv, A

ani n sew Original Filed March 25. 1927 2 Sheets-Sheet 2 Patented Aug. 8, 19 33 GEOMETBICAL INSTRUMENT Leo H. Dawson. Washington, D. 6., assignor, by

assignments, to Wired Radio. Inc., New

York, N. 1L, a Corporation of Delaware Ori ginal application March 5. 178,354. Divided and this application June 26,

1927, Serial No.

1929. Serial No. 313,799

This invention relates broadly to geometrical apparatus. More particularly this invention relates to geometrical apparatus adapted to be employed. in crystallographic operations.

An object of this invention is to provide apparaz us for facilitating the manufacture and production of piezo electric crystal elements for use as frequency control devices in electron discharge device circuits.

Another object of this invention is to provide apparatus for supporting crystalline substances for facilitating examination thereof.

Still another object of this invention is to provide apparatus for supporting crystalline substances in their natural shapes for the determination of a certain axis or certain axes thereof and for use in properly marking the same so as to facilitate cutting operations in suitable relation to said axes.

Other objects and features of this invention will be apparent to those skilled in the art to which this invention pertains from-the following specification and the appended claims.

This application is a divisional application of my U. S. Patent 1,766,037, issued June 24, 1930, for Piezo electric crystal apparatus.

The instrument of my invention was devised to facilitate the proper marking of relatively large pieces of piezo electrically active crystals, such as quartz, with respect to their optical axes for the cutting of the crystals into plates.

According to this invention the rough crystal which is to be marked for cutting is firmly mounted upon a plate member which is pivotally supported upon upright members. members are positioned upon another pivotally mounted'plate member, the position of which may be angularly' adjusted in a direction displaced by from the direction in which the first plate member is adaptedtobe angularly adjusted. This construction permits very flexible angular adjustment of the plate member upon which the crystal under examination is mounted. The second. plate member is pivotally supported by a second set of upright members carried upon a round platform which serves as a turn-table with respect to the base of the entire instrument. Graduated scales are provided adjacent to the various plate members for indicating the angular displacement of each of the plate members. A

pair 'of graduated upright members are provided to the base. A cross bar in adjustable engage-.

ment with the graduated upright members is associated therewith for facilitating the proper The upright (c1. ss- -1) marking of the surfaces of the crystal which is being examined.

In the drawings, Figure 1 is a perspective view of an embodiment of this invention; Fig. 2 illustrates a cross-sectional view of an embodiment of this invention in vertical elevation; and Pig.

3 illustrates another cross-sectional view in ver- 48 are diametrically positioned upon the upper surface of the plate 47 for pivotally supporting the plate 61 through the cooperation of the shaft 49. The plate 4'7 is provided with two trunnions 44 whose common axis is inia plane perpendicular to the shaft 49. By means of the trunnions, the plate 47 is pivotally mounted on the standards 43, the latter being vertically supported by the turn-table or platform 41. A dial 45 is attached to one of the trunnions 44 for indicating the angular displacement of the plane of the plate 4'7 with respect to the plane of platform 41. A vernier 46 is positioned upon one of the standards 43 adjacent to the dial 45 for facilitating the accurate reading of the indications of the dial. The platform 41 is rotatably fastened to the base 40. The periphery of the platform 41 is graduated to provide aconvenient way of determining the magnitude of the angle through which the plate is rotated. A vemier 42 is mounted on the base 40 adjacent to a portion of the periphery of the platform 41 to facilitate the accurate reading of the scale of the platform 41. 4

A pair of graduated positioned upon the base 40. A straight-edge member 68 is adjustably mounted upon the standards 6'1; this straight-edge member is pro-' vided'with a pair of thumb I, screws 69 for adjustvertical standards 67 are ing the position thereof with respect to the standards 6'1. Posts 62 are positioned in selected apertures 61a and 61b which are, provided in the plate 61 for holding a-ci'ystal 66 which is being marked. An armmember 63 is adjustably secured to one of the posts '62 by means of a screw 64. Another screw 65 isprovidedto the M63 for'engaging the crystal 66. The goniometer arrangement of this invention may be employed to facilitate the marking of cutting lines upon crystals prior to the cutting thereof in cases where the crystals are to be divided into crystal plates, the sides of which bear certain definite predetermined angular relations to the axes of the uncut crystal.

Where it is desired to out large and rough piezo electrically active crystals, such as quartz, into relatively small plates, such are employed in controlling the frequency of high frequency oscillation generators, the large crystal 66 is taken and several small slabs or plates are out therefrom. A line is marked upon a certain face of each of these small plates and the position of the optical axis of each small plate with respect to the line drawn on each plate is determined in accordance with the method outlined in my U. S. Patent 1,766,037 of which this application is a divisional application.

The small slabs or plates cut from the large crystal 66 are then replaced in their exact original positions and the crystal 66 is positioned and firmly held upon the plate 61. The position of the optical axis of the large crystal is then determined from the data obtained from the small slabs. The plane of plate 61 is then adjusted until the bar 68 is parallel to the planes of the crystal along which the crystal plates are to be out. For example, where it is desired to cut crystal slabs at a certain angle with respect to the optical axis, the large crystal 66 is placed upon the plate 61 and angularly adjusted until the optical axis thereof is at the proper angle with respect to the horizontal bar 68. Indicia, which are to be used as guides in thecutting of the crystal plates, are then placed upon the large crystal by employing a ruling pen orother suitable instrument for marking the surface of the crystal and using the bar 68 as a guide.

The apparatus of my invention permits the manufacture of piezo electric crystals on a quantity basis. Quartz may be tested with fair rapidity for determining the proper planes on which cuts may be made and thereafter proper identification marks may be placed upon the quartz in order that the cutting tool may be operated in the proper direction. While I have described my invention in certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows: 1. Apparatus for determining the cutting plane of piezo electric plates from a crystalline body comprising a base, a turn-table supported thereon, standards mounted on said turn-table, a plate member pivotally mounted on said standards and carrying a second set of standards, a second plate member pivotally mounted on said second set of standards, means extending substantially normal to said second plate member for securing the crystalline body with respect to said second plate member, and means supported from said base for presenting a straight edge to the crystalline body for use in marking the same along selected planes.

2. Apparatus in accordance with claim 1 including graduated scales whereby the angle of rotation of said turn-table with respect to said straight edge maybe determined.

3. Apparatus in accordance with claim 1 including protractor members and indicia whereby the angles of tilting of the plate members with respect to one. another and with respect to the plane of the turn-table may be determined.

4. Apparatus in accordance with claim 1 in which the axis of rotation of the first said plate member is in a plane perpendicular to the axis of rotation of the second said plate member.

5. Apparatus for marking a crystalline body preparatory to the cutting of plates therefrom comprising a base, a rotatable platform having trunnion supports thereon, a first rockable plate carried by said supports and itself bearing a set of rock shaft supports, a second rockable plate carried by said rock shaft supports and pivoted on an axis extending normal to the axis of said first rockable plate and having means carried thereon for supporting the crystalline body, scale members adjacent said rotatable platform and each of said rockable plates for determining the setting of said second rockable plate, and supporting members extending from said base and carrying a straight-edge member thereon for use in marking said crystalline body according to a predetermined plane.

6. Apparatus in accordance with claim 5 in which is provided a plurality of pins projecting from said second rockable plate for locating said crystalline body thereon.

7. Apparatus for use in marking a crystalline body comprising an adjustable support forsaid crystalline body, a base adapted to serve as a reference plane for angular measurements, means for pivotally supporting said adjustable support from said base, goniometric scales andindices arranged in planes perpendicuar to one anotherfor determining the angular relation of said crystalline body to said base and means for determining the locus of lines on the surface of said crystalline body along the intersection of a predetermined plane with said crystalline body in fixed relation to saidreference plane.

8. Apparatus for use in marking a crystalline body, comprising a base, a first member rotatably mounted thereon, a second member, means for pivotally mounting said second member onsaid first member, a third member, means for pivotally mounting said third member on said second member, means for securing said crystalline body to said third member in a selected position, and means supported from said base for guidance in marking said crystalline body along its intersection with a predetermined plane in fixed relation to said base.

' 9. Apparatus for use in marking a crystalline body comprising a base, a rotatable carrier mounted on said base, a first rockable carrier, means for pivotally mounting said rockable carrier on said rotatable carrier, a second rockable carrier, means for pivotally mounting said second rockable carrier on said first rockable carrier, means supported by said second rockable carrier for securing a crystalline body in a predetermined position wtih respect to saidbase, and means supported from said base for guidance in marking said crystalline body along its intersection with a selected plane.

10. Apparatus for use in marking a crystalline body comprising a base, a rotatable member mounted thereon, a first rockable member, means for pivotally mounting said first rockable member on said rotatable member, a second rockable member, means for pivotally mounting said second rockable member on said first rockable memher along an axis substantially normal to the axis of rotation of said first rockable member, a

lar relation to said base.

11. Apparatus for use in marking a crystalline body comprising a base, a rotatable member a mounted thereon, a first rockable member carried by said rotatable member, a second rockable member carried by said first rockable member and pivotally mounted on an axis at right angles to the axis of rotation of said first rockable member, said second rockable member having means for centering and supporting a crystalline body, scale members associated with said rotatable members and with said rockable members for setting said crystalline body in a predetermined angular relationship to said base, a straight-edge member, and means supported by said base for holding said straight-edge member in position to be of guidance in marking said crystalline body on its intersection with a predetermined plane.

12. Apparatus for use in marking a crystalline crystalline body,

body along its intersection with a predetermined plane comprising a universal mounting for said said mounting including a base adapted as a reference plane for goniometric measurements and means to adjust and hold said crystalline body in a predetermined angular relationship to said reference plane, and means of guidance in marking said crystalline body on a line parallel with said reference plane.

13. Apparatus for use in marking a crystalline body along its intersection with a predetermined plane, comprising a universal mounting for said crystalline body, said mounting including a base adapted as a reference plane for gon'iometric measurements, protractor scales adapted to determine the adjustments of said universal mounting, said mounting being adjustable to hold said crystalline body in a predetermined angular relationship to said reference plane in accordance with the indications of said protractor scales, and means extending from said base for providing a marking guide parallel with said reference plane.

LEO H. DAWSON. 

